1. Technical Field
The present invention relates to a spectacle lens design method for designing a presbyopia correcting progressive-power lens attached to a spectacle frame having a large bend angle such as a wraparound-type frame.
2. Related Art
Recently, a wraparound-type spectacle frame chiefly for sport sunglasses has been increasingly used. FIGS. 3A and 3B are perspective views of an example of wraparound-type spectacle frame as viewed obliquely and from above, respectively. As illustrated in FIGS. 3A and 3B, the wraparound-type spectacle frame having a large bend angle is curved along the shape of the wearer's face. Thus, lenses attached to the wraparound frame reach the sides of the face, and provide wide vision. For this reason the wraparound-type spectacle frame is used for spectacles such as protection spectacles for sports and eyeball protection spectacles to be worn by athletes.
With rise in the number of the athletes wearing wraparound-type spectacle frames, ordinary people wearing the wraparound-type frame are also increasing. Thus, an increasing number of people who need correcting glasses desire to use the wraparound-type spectacle frame.
In order to meet this demand, JP-A-2005-284059 discloses an optical design method appropriate for a spectacle frame having a large bend angle such as a wraparound-type frame.
However, the optical design method disclosed in the above reference does not include a design method for a presbyopia correcting progressive-power lens. Recently, there is a demand for using the wraparound-type sport spectacle frame for the progressive-power lens which corrects hyperopia and myopia by one lens.